Switch



Sept. 12, 1961 Filed NOV. 13. 1957 G. F. KINCAID ETAL SWITCH 2 Sheets-Sheet 1 f/'y' C7 s l /v y 7 lb C@ zc 2B ffy- 2 INVENToRS BY W Sept. 12, 1961 G. F. KlNcAlD l-:TAL

SWITCH 2 Sheets-Sheel'l 2 Filed NOV. 13. 1957 ALL? INVENTOS l Y .Il f

Patented Sept. 12, 1961 2,999,912 SWITCH George F. Kincaid, Bradley C. Douglas, and Benjamin A.

Gay, St..Lonis, Mo., assignors to Atlas Powder Company, Wilmington, Del., a corporation of Delaware Filed Nov. 13, 1957, Ser. No. 696,074 "Claims. (Cl. 20o- 82) This application relates to a switch and is par-ticularly related to a squib-actuated, plunger-type switch of improved design possessing exceptional stability.

Certain types of projectiles and missiles adapted for travel at-high speeds require the use of switches that are highly reliable and of outstanding stability. Such devices also require the use of switches that provide strong positive contact free from chatter or vibration and of low contact resistance. It is therefore an object of the present invention to provide a switch of extremely rugged construction ywhich is able to withstand shock in all directions.

Another object of -the present invention is to provide a switch that is highly reliable and capable of carrying high amperage and voltage without jump or breakdown.

A still further object of the present invention is to provide a switch of very small size and of low contact resistance.

The switch of the present invention comprises in combination a switch housing and at least one electrical contact member attached to said housing. At least one other electrical contact member is attached to a slide member mounted in the switch housing for longitudinal movement. The slide member is so shaped in relation to the 'housing that lateral and rotational movement in any direction within the housing is prevented. The slide member is provided as hereinabove set out with longitudinal movement avi-thin fthe housing such that electrical contact is made and broken between the electrical contact members attached to the switch housing and the electrical contact members attached to the slide member. A squib may be located within the switch housing in such manner that 'when the squib is fired a 'piston is driven forward.- The piston is operatively attached to the slide member so that the flexible contactors which are mounted in the slide member make or break contact 'with the fixed contactors which are mounted in the switch housmg.

The advantages and improvements in the switch of the present invention will be apparent from the following description of the invention taken in connection with the accompanying drawings wherein:

FIGURE l is a plan View of an embodiment of the invention.

FIGURE 2 is a View in section, taken along line A-A of FIGURE 1.

FIGURE 3 is a view in section, taken along line B-B of FIGURE l.

FIGURE 4 is a view simi-lar to FIGURE 3 except that the squib has been fired and the switch has been actuated.

FIGURE 5 is a section taken along line C-C of FIG- URE 2.

FIGURE 6 `is a section of an alternate embodiment of the invention.

FIGURE 7 is an exploded View of the switch.

Referring now to the drawings in which like numerals and references are employed to designate like parts throughout the several views; the numeral 2 refers to the switch casing and 4 is a flexible contactor holder, fabricated from Teflon, nylon, other plastic or suitable non-conducting material. The holder 4 when crimped into the switch casing 2 provides with the caisng a complete housing for the .Switch elements which is referred to throughout the specification and claims as the switch housing.

A plurality of fixed contact members 8, are serially attached along 'the length of the fixed contactor holder 4. The fixed contact holder 4, containing the fixed contact members 8, is assembled with the switch casing 2, and forms the top element of the switch housing. Fixed contacter yholder 4, is further provided with a longitudinal groove E18, which is adapted to receive and partially support a slide member 10, also made of nylon or other suitable non-conducting material, said slide meinber 1-0, having xedly attached therein a plurality of serially arranged lflexible contact members 6, which are fabricated from a suitable electrical conducting material. The flexible contact members being so mounted in the slide member 10, that they may be each operatively engaged or disengaged from the fixed contact members 8, which are mounted in the xed contactor holder 4, upon forward movement of the slide member i0, during lthe operation of the switch.

It will be noted that slide member 10, is provided with opposed flat bearing surfaces `which are closely adjacent to casing 2, and contact pin holder 4 respectively. Slide member 10, is also provided with opposed flat bearing surfaces at right angles thereto. Two of these llat bearing surfaces are on each side of slide mem-ber 10. One such bearing surface lis against switch casing 2, and the other is against the side of fixed contact holder 4. In this way, slide member 10, is provided with a very great degree of stability against lateral motion, both of an up and down and side to side variety. Moreover, the bearing surfaces extend on both ends above and below the area in ywhich contact members 6, are located on slide member 10. In this way stability against a twisting or cantilever action is provided in all directions.

The fixed contact holder 4, is further provided with a retaining lip 11, at one end thereof, which lip is adapted to receive the llirst or foremost flexible contact member 6, mounted in the slide member 19, after the slide member has been driven to its most forward position. Upon ring of the switch the two foremost contact members spring out into engagement with retaining lip I1, thereby preventing the slide member 10, from returning to its original position within the switch housing and providing positive locking of slide member 1d, against an inner wall of the switch casing 2, when in the fired position (see FIGURE 4). It has been found desirable to gold plate the fixed contact members S, and the flexible contact members 6, in order to provide for a lower resistance path for the electric current.

Behind each flexible contact member 6, mounted in said slide member 10, is located a projection or bead 9, of such size that when said flexible contact members 6, are flexed or bent in the normal operation of the switch, the flexible contact members 6, are bent on a radius and retain their springiness and shape. The projections or beads l9, also promote firm positive contact pressure between the flexible contact members 6, and the xed contact -members 8, and prevent the flexible contact members 6, from cracking or breaking upon firing of the switch.

Slide member 10, is provided with a key slot 22, having a tapered or inclined surface 24, adapted for receiving an enlarged section 17, of a piston 12. 'I'he other end of said piston 12, is also enlarged and flared as at 15. At least the flared portion 15, of piston 12, is made of soft malleable metal, as for example aluminum. In assembling piston 12 in the switch casing 2 and slide member 10, enlarged section 17 is forced into key slot 22, against inclined surface 424, so lthat the flared surface 15, of piston 12, is seated firmly against a bearing surface 26 of switch casing 2; and slide member 10 is held rigidly against an inner wall of switch casing 2, Piston V1.2, the-re.-

fore is held under longitudinal tension between slide member and switch casing 2, prior to activation of the switch. Thus the slide member l0, is positioned within casing 2, with a high degree of longitudinal stability. The positive seating of fiare l5, within the switch housing provides a completely sealed enclosure for entrapping the gases which are expelled upon the firing of a squib 2l. Squib 2l is encased in squib holder 20, and squib holder is crimped into the switch casing 2 in gas tight manner. The power `charge in squib 21, is a low explosive gas-producing charge which when fired produces a sufficient quantity of gas to overcome the structural strength of fiare 15, and pushes the piston 12, and the slide member l0, to its forward limiting position.

It has been found desirable to fabricate squib holder 2t) of metal; said holder having a cavity to receive the squib, which contains a gas-producing charge such as, for example, a mixture of lead mononitroresorcinate and potassium nitrate (95/5) pressed at approximately 5,000 p.s.i. in intimate contact with an electric igniter assembly, from which wire leads extend through a hole in said squib holder.

In the normal operation of the explosive switch an electric current is brought, by means of lead wires 25, to the squib 2l, said electric current firing the squib 21. The gases produced by the firing of the squib 21 push against piston 12 with sufiicient force that the iiared portion l5 is deformed, and piston 12, and slide member 10, to which the piston is attached are driven to the forward position of slide member 10, asy illustrated in FIG- URE 4. Thus, flexible contact members 6, which are not in operative `contact with fixed contact members 8, are brought into contact, and at the same time those ilexible contact members which were formerly engaged in operative contact with the fixed contact members and thereupon disengaged.

While the specific embodiment above illustrated shows a switch comprising a normally closed circuit and three normally open `circuits capable of carrying high currents for a short period of time without jump or break-down, it is within the scope of the present invention to fabricate a switch comprising various combinations of open and closed circuits. IIn addition, two or more of such switches may be effectively joined together such that upon firing of the squib a number of slide members are driven forwardvcarrying with them their respective contact members to thereupon `close the normally' open circuits and open the normally closed circuits.

It may also be desirable to incorporate a delay element in the operation of the above described switch. For example, a pyrotechnic delay element may be positioned ahead of the gas-producing charge of squib member 21.

It is also within the scope of the present invention to provide other means of actuating slide member 10, such as, for example, a triggered spring or compressed gas.

It will also be apparent that although in the specific embodiment of the invention of FIGURES l through 5 and 7 the fiexible contactors 6, have been described as being attached to the slide member 10, and the fixed contact members S, have been described as being attached to the fixed contact holder 4, the reverse arrangement is entirely possible and may be used. ln this case, an embodiment of which is shown in FIGURE 6 wherein parts analogous to those on the other figures are given similar numbers, flexible contact members 6 will be located on fixed contact holder 4, instead of on the slide member 10, and fixed contact members 8 will be located on slide member 10 instead of on contact holder 4.

It is noted that wherever flexible members, such as 19' and 6 are employed it has been found desirable to provide projections or beads for support of the flexible mem# ber such as shown at 9 of FIGURE 6.

In addition to the reversal of the fixed and flexible contact members as illustrated in the specific embodiment shown in FIGURE 6 it will be seen that slide member 10 is provided with exible, locking members 19' which upon activation of the switch will spring into engagement with retaining lip 11, thereby preventing the slide mem ber 10 from returning to its original position within the switch housing and providing positive locking of slide member 10 against an inner wall of the switch casing 2, when inthe red positien.`

While a particular embodiment of the present invention has been illustrated and described wherein, it is intended to limit the invention to such a disclosure and changes and modifications may be incorporated and embodied therein within the scope of the following claims.

We claim:

1. A switch comprising in combination a switch housing, at least one electrical contact member attached to said housing, a rigid movable nonconducting slide member carrying a second electrical contact member, said slide member mounted in said housing for longitudinal movement and so shaped in relation to said housing that lateral movement in any Idirection within the housing and rotational movement within the housing is prevented, by means of rigid, contacting, bearing surfaces between said slide member and said housing and independent of said electrical contacts, said slide member being adapted for longitudinal movement within said housing to two positions, at one position said first electrical contact member and said second electrical contact member being operatively engaged and in the other position said first electrical contact member being disengaged from operative contact with said second electrical contact member, means for rigidly holding said slide member in one of said positions, and means for moving said slide member longitudinally within said housing from one of said positions to the other position which comprises a piston and an explosive squib.

2. KAn explosively operated switch which comprises in combination a switch housing, at least one Contact member attached to said housing, a rigid, moveable, nonconducting slide member carrying a second contact member, said lslide member being mounted in said housing for longitudinal movement to two limiting positions, at one position said first electrical contact member being operatively engaged, and in the other position said first contact member being disengaged, from operative contact with a second electrical Contact member, said slide member being so shaped and mounted in relation to said housing that lateral movement in any direction within the housing and rotational movement within the housing is prevented, means urging said slide member in such manner that said slide member is pressed against said switch housing in one of said limiting positions, means for driving said slide member which comprises an explosive squib and means of firing said squib.

3. An explosively operated switch which comprises in combination a switch housing, a plurality of fixed electrical Contact members fxedly attached to said housing and arranged serially along its length, a rigid non-conducting movable slide member carrying a plurality of flexible contact members arranged serially along its length said fiexible contact members extending through said slide member to maintain electrical contact with said fixed electrical contact members as the slide member moves longitudinally within said housing, said slide member being supported in said housing against lateral and rotational movement by flat opposed surfaces on at least four sides a-t least two surfaces of which are arranged at right angles, a piston attached to said slide member in such manner that said slide member is wedged against said switch housing such that said piston is under longitudinal tension prior to activation of the switch, means of driving said plunger and said slide member which comprises an explosive squib and means of firing said squib.

4. An explosively operated switch which comprises in combination a switch housing, a plurality of fixed electrical contact members iixedly attached to said housing and arranged serially along its length, a rigid non-conducting movable slide member carrying a plurality of flexible contact members arranged serially along its length, said ilexible electrical contact members being further arranged to engage said exible contact members as said slide member moves within said housing, said slide member being supported in said housing against lateral and rotational movement by ilat opposed surfaces on at least -four sides at least two surfaces of which are arranged at right angles, a piston affixed to said slide member by means of an inclined surface which serves to draw said slide member against said housing such that said piston is under longi-tudinal tension and said piston and said slide member are prevented from longitudinal movement in any direction prior to activation of the switch, said piston being further provided with lonigtudinal stability by means of a ange destructible upon activation of the switch means for driving said piston and said slide member carrying said contact members which comprises an explosive squib and means of tiring said squib.

5. An explosively operated switch which comprises in combination a switch housing, a plurality of fixed electrical contact members xedly attached to said housing and arranged serially along its length, a rigid non-conducting movable slide member carrying a plurality of exible contact members arranged serially along its length and extending through said slide member, a plurality of projected surfaces, one of each of said surfaces being i located behind each projecting ileixble contact member,

the arrangement of said flexible contact members being such that electrical contact is made and broken by sliding movement of said slide member wi-thin said housing, said slide member being supported in said housing against lateral and rotational movement by at opposed right angle surfaces on at least two sides, a piston aixed to said slide member by means of a `tapered key slot which serves to draw said slide member against said housing such that said piston is under longitudinal ten-sion and said piston and said slide member are prevented from moving longitudinally in any direction prior to activation of the switch, a destructible anged member attached to said piston in confined space relationship to an explosive squib and means for moving said piston and said movable slide member, and means for locking said slide member in its tired position.

References Cited in the file of this patent UNITED STATES PATENTS 285,778 Adams Oct. 2, 1883 :3,484 Jewell June 2, 189|1 1,617,862 Pistor Feb. 15, 1927 1,671,196 Larson May 29, 1928 2,249,977 Penfold July 22, 1941 2,521,561 Batcheller Sept. 5, 1950 2,564,957 Cermak Aug. 21, 1951 2,575,447 Unsworth Nov. 13, 1951 2,594,644 Hansen Apr. 29, 1952 2,712,791 Bleakney July 12, 1955 2,816,196 Daudelin Dec. 10, 1957 

